bin/named/server.c

	server.c revision 3a725776198408631c3264f409410c1d13df64b9
/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* $Id: server.c,v 1.203 2000/07/10 22:02:38 tale Exp $ */

#include <config.h>

#include <stdlib.h>

#include <isc/app.h>
#include <isc/base64.h>
#include <isc/dir.h>
#include <isc/entropy.h>
#include <isc/lex.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/timer.h>
#include <isc/util.h>

#include <dns/cache.h>
#include <dns/confparser.h>
#include <dns/db.h>
#include <dns/dispatch.h>
#include <dns/journal.h>
#include <dns/keytable.h>
#include <dns/peer.h>
#include <dns/rdatastruct.h>
#include <dns/resolver.h>
#include <dns/rootns.h>
#include <dns/tkey.h>
#include <dns/tkeyconf.h>
#include <dns/tsigconf.h>
#include <dns/view.h>
#include <dns/zone.h>
#include <dns/zoneconf.h>

#include <dst/dst.h>

#include <named/client.h>
#include <named/interfacemgr.h>
#include <named/log.h>
#include <named/logconf.h>
#include <named/omapi.h>
#include <named/os.h>
#include <named/server.h>

/*
 * Check an operation for failure.  Assumes that the function
 * using it has a 'result' variable and a 'cleanup' label.
 */
#define CHECK(op) \
    do { result = (op);                      \
           if (result != ISC_R_SUCCESS) goto cleanup;    \
    } while (0)

#define CHECKM(op, msg) \
    do { result = (op);                       \
           if (result != ISC_R_SUCCESS) {             \
            isc_log_write(ns_g_lctx,          \
                      NS_LOGCATEGORY_GENERAL,     \
                      NS_LOGMODULE_SERVER,    \
                      ISC_LOG_ERROR,          \
                      "%s: %s", msg,          \
                      isc_result_totext(result)); \
            goto cleanup;                 \
        }                         \
    } while (0)                       \

#define CHECKFATAL(op, msg) \
    do { result = (op);                       \
           if (result != ISC_R_SUCCESS)           \
            fatal(msg, result);           \
    } while (0)                       \

typedef struct {
    isc_mem_t *     mctx;
    dns_viewlist_t      viewlist;
    dns_aclconfctx_t    *aclconf;
} ns_load_t;

static void
fatal(const char *msg, isc_result_t result);

static void
ns_server_reload(isc_task_t *task, isc_event_t *event);

static isc_result_t
ns_listenelt_fromconfig(dns_c_lstnon_t *celt, dns_c_ctx_t *cctx,
            dns_aclconfctx_t *actx,
            isc_mem_t *mctx, ns_listenelt_t **target);
static isc_result_t
ns_listenlist_fromconfig(dns_c_lstnlist_t *clist, dns_c_ctx_t *cctx,
             dns_aclconfctx_t *actx,
             isc_mem_t *mctx, ns_listenlist_t **target);

/*
 * Configure a single view ACL at '*aclp'.  Get its configuration by
 * calling 'getvcacl' (for per-view configuration) and maybe 'getscacl'
 * (for a global default).
 */
static isc_result_t
configure_view_acl(dns_c_view_t *cview,
           dns_c_ctx_t *cctx,
           dns_aclconfctx_t *actx, isc_mem_t *mctx,
           isc_result_t (*getvcacl)
               (dns_c_view_t *, dns_c_ipmatchlist_t **),
           isc_result_t (*getscacl)
               (dns_c_ctx_t *, dns_c_ipmatchlist_t **),
           dns_acl_t **aclp)
{
    isc_result_t result;

    dns_c_ipmatchlist_t *cacl = NULL;
    if (*aclp != NULL)
        dns_acl_detach(aclp);
    if (getvcacl != NULL && cview != NULL)
        (void)(*getvcacl)(cview, &cacl);
    if (cacl == NULL && getscacl != NULL)
        (void)(*getscacl)(cctx, &cacl);
    if (cacl == NULL) {
        /*
         * No value available.  *aclp == NULL.
         */
        return (ISC_R_SUCCESS);
    }

    result = dns_acl_fromconfig(cacl, cctx, actx, mctx, aclp);

    dns_c_ipmatchlist_detach(&cacl);

    return (result);
}

/*
 * Convert a null-terminated string of base64 text into binary,
 * storing it in a buffer.  'mctx' is only used internally.
 */
static isc_result_t
base64_cstring_tobuffer(isc_mem_t *mctx, char *cstr, isc_buffer_t *target) {
    isc_result_t result;
    isc_buffer_t source;
    isc_lex_t *lex = NULL;
    isc_boolean_t isopen = ISC_FALSE;

    isc_buffer_init(&source, cstr, strlen(cstr));
    isc_buffer_add(&source, strlen(cstr));
    CHECK(isc_lex_create(mctx, 256, &lex));
    CHECK(isc_lex_openbuffer(lex, &source));
    isopen = ISC_TRUE;
    CHECK(isc_base64_tobuffer(lex, target, -1));

 cleanup:
    if (isopen)
        (void)isc_lex_close(lex);
    if (lex != NULL)
        isc_lex_destroy(&lex);
    return (result);
}

/*
 * Configure DNSSEC keys for a view.  Currently used only for
 * the security roots.
 *
 * The per-view configuration values and their server-global
 * defaults are are read from 'cview' and 'cctx' using
 * the function 'cgetv' and 'cgets', respectively.
 * The variable to be configured is '*target'.
 */
static isc_result_t
configure_view_dnsseckeys(dns_c_view_t *cview,
              dns_c_ctx_t *cctx,
              isc_mem_t *mctx,
              isc_result_t (*cgetv)
                  (dns_c_view_t *, dns_c_tkeylist_t **),
              isc_result_t (*cgets)
                  (dns_c_ctx_t *, dns_c_tkeylist_t **),
              dns_keytable_t **target)
{
    isc_result_t result;
    dns_c_tkeylist_t *ckeys = NULL;
    dns_c_tkey_t *ckey;
    dns_keytable_t *keytable = NULL;
    dst_key_t *dstkey = NULL;

    CHECK(dns_keytable_create(mctx, &keytable));

    result = ISC_R_FAILURE;
    if (cgetv != NULL && cview != NULL)
        result = (*cgetv)(cview, &ckeys);
    if (result != ISC_R_SUCCESS)
        result = (*cgets)(cctx, &ckeys);

    if (result == ISC_R_SUCCESS) {
        for (ckey = ISC_LIST_HEAD(ckeys->tkeylist);
             ckey != NULL;
             ckey = ISC_LIST_NEXT(ckey, next))
        {
            dns_rdataclass_t viewclass;
            dns_rdata_key_t keystruct;
            isc_int32_t flags, proto, alg;
            unsigned char keydata[4096];
            isc_buffer_t keydatabuf;
            unsigned char rrdata[4096];
            isc_buffer_t rrdatabuf;
            isc_region_t r;
            dns_fixedname_t fkeyname;
            dns_name_t *keyname;
            isc_buffer_t namebuf;

            if (cview == NULL)
                viewclass = dns_rdataclass_in;
            else
                CHECK(dns_c_view_getviewclass(cview,
                                  &viewclass));
            keystruct.common.rdclass = viewclass;
            keystruct.common.rdtype = dns_rdatatype_key;
            /*
             * The key data in keystruct is not
             * dynamically allocated.
             */
            keystruct.mctx = NULL;

            ISC_LINK_INIT(&keystruct.common, link);

            flags = ckey->pubkey->flags;
            proto = ckey->pubkey->protocol;
            alg = ckey->pubkey->algorithm;
            if (flags < 0 || flags > 0xffff)
                CHECKM(ISC_R_RANGE, "key flags");
            if (proto < 0 || proto > 0xff)
                CHECKM(ISC_R_RANGE, "key protocol");
            if (alg < 0 || alg > 0xff)
                CHECKM(ISC_R_RANGE, "key algorithm");
            keystruct.flags = flags;
            keystruct.protocol = proto;
            keystruct.algorithm = alg;

            isc_buffer_init(&keydatabuf, keydata, sizeof(keydata));
            isc_buffer_init(&rrdatabuf, rrdata, sizeof(rrdata));

            CHECK(base64_cstring_tobuffer(mctx, ckey->pubkey->key,
                              &keydatabuf));
            isc_buffer_usedregion(&keydatabuf, &r);
            keystruct.datalen = r.length;
            keystruct.data = r.base;

            CHECK(dns_rdata_fromstruct(NULL,
                           keystruct.common.rdclass,
                           keystruct.common.rdtype,
                           &keystruct, &rrdatabuf));
            dns_fixedname_init(&fkeyname);
            keyname = dns_fixedname_name(&fkeyname);
            isc_buffer_init(&namebuf, ckey->domain,
                    strlen(ckey->domain));
            isc_buffer_add(&namebuf, strlen(ckey->domain));
            CHECK(dns_name_fromtext(keyname, &namebuf,
                        dns_rootname, ISC_FALSE,
                        NULL));
            CHECK(dst_key_fromdns(keyname, &rrdatabuf, mctx,
                          &dstkey));

            CHECK(dns_keytable_add(keytable, &dstkey));
            INSIST(dstkey == NULL);
        }
    } else if (result != ISC_R_NOTFOUND)
        goto cleanup;

    dns_keytable_detach(target);
    *target = keytable; /* Transfer ownership. */
    keytable = NULL;
    result = ISC_R_SUCCESS;

 cleanup:
    if (dstkey != NULL)
        dst_key_free(&dstkey);
    return (result);
}


/*
 * Get a dispatch appropriate for the resolver of a given view.
 */
static isc_result_t
get_view_querysource_dispatch(dns_c_ctx_t *cctx, dns_c_view_t *cview,
                  int af, dns_dispatch_t **dispatchp)
{
    isc_result_t result;
    dns_dispatch_t *disp;
    isc_sockaddr_t sa;
    unsigned int attrs, attrmask;

    /*
     * Make compiler happy.
     */
    result = ISC_R_FAILURE;

    switch (af) {
    case AF_INET:
        result = ISC_R_NOTFOUND;
        if (cview != NULL)
            result = dns_c_view_getquerysource(cview, &sa);
        if (result != ISC_R_SUCCESS)
            result = dns_c_ctx_getquerysource(cctx, &sa);
        if (result != ISC_R_SUCCESS)
            isc_sockaddr_any(&sa);
        break;
    case AF_INET6:
        result = ISC_R_NOTFOUND;
        if (cview != NULL)
            result = dns_c_view_getquerysourcev6(cview, &sa);
        if (result != ISC_R_SUCCESS)
            result = dns_c_ctx_getquerysourcev6(cctx, &sa);
        if (result != ISC_R_SUCCESS)
            isc_sockaddr_any6(&sa);
        break;
    default:
        INSIST(0);
    }

    INSIST(isc_sockaddr_pf(&sa) == af);

    /*
     * If we don't support this address family, we're done!
     */
    switch (af) {
    case AF_INET:
        result = isc_net_probeipv4();
        break;
    case AF_INET6:
        result = isc_net_probeipv6();
        break;
    default:
        INSIST(0);
    }
    if (result != ISC_R_SUCCESS)
        return (ISC_R_SUCCESS);

    /*
     * Try to find a dispatcher that we can share.
     */
    attrs = 0;
    attrs |= DNS_DISPATCHATTR_UDP;
    switch (af) {
    case AF_INET:
        attrs |= DNS_DISPATCHATTR_IPV4;
        break;
    case AF_INET6:
        attrs |= DNS_DISPATCHATTR_IPV6;
        break;
    }
    attrmask = 0;
    attrmask |= DNS_DISPATCHATTR_UDP;
    attrmask |= DNS_DISPATCHATTR_TCP;
    attrmask |= DNS_DISPATCHATTR_IPV4;
    attrmask |= DNS_DISPATCHATTR_IPV6;

    disp = NULL;
    result = dns_dispatch_getudp(ns_g_dispatchmgr, ns_g_socketmgr,
                     ns_g_taskmgr, &sa, 4096,
                     1000, 32768, 16411, 16433,
                     attrs, attrmask, &disp);
    if (result != ISC_R_SUCCESS) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER,
                  ISC_LOG_ERROR,
                  "could not get query source dispatcher");
        return (result);
    }

    *dispatchp = disp;

    return (ISC_R_SUCCESS);
}

/*
 * Configure 'view' according to 'cview', taking defaults from 'cctx'
 * where values are missing in cctx.
 *
 * When configuring the default view, cctx will be NULL and the
 * glboal defaults in cview used exclusively.
 */
static isc_result_t
configure_view(dns_view_t *view, dns_c_ctx_t *cctx, dns_c_view_t *cview,
           isc_mem_t *mctx, dns_aclconfctx_t *actx)
{
    dns_cache_t *cache = NULL;
    isc_result_t result;
    isc_uint32_t cleaning_interval;
    dns_tsig_keyring_t *ring;
    dns_c_forw_t forward;
    dns_c_iplist_t *forwarders;
    dns_fwdpolicy_t fwdpolicy;
    isc_sockaddrlist_t addresses;
    isc_sockaddr_t *sa, *next_sa;
    dns_view_t *pview = NULL;   /* Production view */
    unsigned int i;
    isc_mem_t *cmctx;
    dns_dispatch_t *dispatch4 = NULL;
    dns_dispatch_t *dispatch6 = NULL;
    in_port_t port;

    REQUIRE(DNS_VIEW_VALID(view));

    ISC_LIST_INIT(addresses);
    cmctx = NULL;

    RWLOCK(&view->conflock, isc_rwlocktype_write);

    /*
     * Set the view's port number for outgoing queries.
     */
    result = dns_c_ctx_getport(cctx, &port);
    if (result != ISC_R_SUCCESS)
        port = 53;
    dns_view_setdstport(view, port);

    /*
     * Configure the view's cache.  Try to reuse an existing
     * cache if possible, otherwise create a new cache.
     * Note that the ADB is not preserved in either case.
     *
     * XXX Determining when it is safe to reuse a cache is
     * tricky.  When the view's configuration changes, the cached
     * data may become invalid because it reflects our old
     * view of the world.  As more view attributes become
     * configurable, we will have to add code here to check
     * whether they have changed in ways that could
     * invalidate the cache.
     */
    result = dns_viewlist_find(&ns_g_server->viewlist,
                   view->name, view->rdclass,
                   &pview);
    if (result != ISC_R_NOTFOUND && result != ISC_R_SUCCESS)
        goto cleanup;
    if (pview != NULL) {
        INSIST(pview->cache != NULL);
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER,
                  ISC_LOG_DEBUG(3), "reusing existing cache");
        dns_cache_attach(pview->cache, &cache);
        dns_view_detach(&pview);
    } else {
        CHECK(isc_mem_create(0, 0, &cmctx));
        CHECK(dns_cache_create(cmctx, ns_g_taskmgr, ns_g_timermgr,
                       view->rdclass, "rbt", 0, NULL, &cache));
    }
    dns_view_setcache(view, cache);

    result = ISC_R_NOTFOUND;
    if (cview != NULL)
        result = dns_c_view_getcleaninterval(cview,
                             &cleaning_interval);
    if (result != ISC_R_SUCCESS)
        result = dns_c_ctx_getcleaninterval(cctx, &cleaning_interval);
    if (result != ISC_R_SUCCESS)
        cleaning_interval = 3600; /* Default is 1 hour. */
    dns_cache_setcleaninginterval(cache, cleaning_interval);

    dns_cache_detach(&cache);

    /*
     * XXXRTH  Temporary support for loading cache contents.
     */
    if (ns_g_cachefile != NULL) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER,
                  ISC_LOG_DEBUG(1), "loading cache '%s'",
                  ns_g_cachefile);
        CHECK(dns_db_load(view->cachedb, ns_g_cachefile));
    }

    /*
     * Resolver.
     *
     * XXXRTH  Hardwired number of tasks.
     */
    CHECK(get_view_querysource_dispatch(cctx, cview, AF_INET,
                        &dispatch4));
    CHECK(get_view_querysource_dispatch(cctx, cview, AF_INET6,
                        &dispatch6));
    CHECK(dns_view_createresolver(view, ns_g_taskmgr, 31,
                      ns_g_socketmgr, ns_g_timermgr,
                      0, ns_g_dispatchmgr,
                      dispatch4, dispatch6));
    if (dispatch4 != NULL)
        dns_dispatch_detach(&dispatch4);
    if (dispatch6 != NULL)
        dns_dispatch_detach(&dispatch6);

    /*
     * Set resolver forwarding policy.
     */
    if ((cview != NULL &&
         dns_c_view_getforwarders(cview, &forwarders) == ISC_R_SUCCESS) ||
        (dns_c_ctx_getforwarders(cctx, &forwarders) == ISC_R_SUCCESS))
    {
        fwdpolicy = dns_fwdpolicy_first;
        /*
         * Ugh.  Convert between list formats.
         */
        for (i = 0; i < forwarders->nextidx; i++) {
            sa = isc_mem_get(view->mctx, sizeof *sa);
            if (sa == NULL) {
                result = ISC_R_NOMEMORY;
                goto cleanup;
            }
            *sa = forwarders->ips[i];
            isc_sockaddr_setport(sa, port);
            ISC_LINK_INIT(sa, link);
            ISC_LIST_APPEND(addresses, sa, link);
        }
        INSIST(!ISC_LIST_EMPTY(addresses));
        dns_c_iplist_detach(&forwarders);
        CHECK(dns_resolver_setforwarders(view->resolver, &addresses));
        /*
         * XXXRTH  The configuration type 'dns_c_forw_t' should be
         *         eliminated.
         */
        if ((cview != NULL &&
             dns_c_view_getforward(cview, &forward) == ISC_R_SUCCESS)
            || dns_c_ctx_getforward(cctx, &forward) == ISC_R_SUCCESS) {
            INSIST(forward == dns_c_forw_first ||
                   forward == dns_c_forw_only);
            if (forward == dns_c_forw_only)
                fwdpolicy = dns_fwdpolicy_only;
        }
        CHECK(dns_resolver_setfwdpolicy(view->resolver, fwdpolicy));
    }

    /*
     * We have default hints for class IN if we need them.
     */
    if (view->rdclass == dns_rdataclass_in && view->hints == NULL)
        dns_view_sethints(view, ns_g_server->in_roothints);

    /*
     * If we still have no hints, this is a non-IN view with no
     * "hints zone" configured.  That's an error.
     */
    if (view->hints == NULL) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "no root hints for view '%s'",
                  cview == NULL ? "<default>" : cview->name);
        result = ISC_R_FAILURE;
        goto cleanup;
    }

    /*
     * Configure the view's TSIG keys.
     */
    ring = NULL;
    CHECK(dns_tsigkeyring_fromconfig(cview, cctx, view->mctx, &ring));
    dns_view_setkeyring(view, ring);

    /*
     * Configure the view's peer list.
     */
    {
        dns_peerlist_t *newpeers = NULL;

        result = ISC_R_NOTFOUND;
        if (cview != NULL)
            result = dns_c_view_getpeerlist(cview, &newpeers);
        if (result != ISC_R_SUCCESS)
            result = dns_c_ctx_getpeerlist(cctx, &newpeers);
        if (result != ISC_R_SUCCESS)
            result = dns_peerlist_new(mctx, &newpeers);
        CHECK(result);

        dns_peerlist_detach(&view->peers);
        view->peers = newpeers; /* Transfer ownership. */
    }

    /*
     * Configure the "match-clients" ACL.
     */
    CHECK(configure_view_acl(cview, cctx, actx, ns_g_mctx,
                 dns_c_view_getmatchclients, NULL,
                 &view->matchclients));

    /*
     * Configure other configurable data.
     */
    view->recursion = ISC_TRUE;
    (void)dns_c_ctx_getrecursion(cctx, &view->recursion);
    if (cview != NULL)
        (void)dns_c_view_getrecursion(cview, &view->recursion);

    view->auth_nxdomain = ISC_FALSE; /* Was true in BIND 8 */
    (void)dns_c_ctx_getauthnxdomain(cctx, &view->auth_nxdomain);
    if (cview != NULL)
        (void)dns_c_view_getauthnxdomain(cview, &view->auth_nxdomain);

    result = ISC_R_NOTFOUND;
    if (cview != NULL)
        result = dns_c_view_gettransferformat(cview,
                              &view->transfer_format);
    if (result != ISC_R_SUCCESS)
        result = dns_c_ctx_gettransferformat(cctx,
                             &view->transfer_format);
    if (result != ISC_R_SUCCESS)
        view->transfer_format = dns_many_answers;

    CHECK(configure_view_acl(cview, cctx, actx, ns_g_mctx,
                 dns_c_view_getallowquery,
                 dns_c_ctx_getallowquery,
                 &view->queryacl));

    CHECK(configure_view_acl(cview, cctx, actx, ns_g_mctx,
                 dns_c_view_getrecursionacl,
                 dns_c_ctx_getallowrecursion,
                 &view->recursionacl));

    result = ISC_R_NOTFOUND;
    if (cview != NULL)
        result = dns_c_view_getrequestixfr(cview, &view->requestixfr);
    if (result != ISC_R_SUCCESS)
        result = dns_c_ctx_getrequestixfr(cctx, &view->requestixfr);
    if (result != ISC_R_SUCCESS)
        view->requestixfr = ISC_TRUE;

    result = ISC_R_NOTFOUND;
    if (cview != NULL)
        result = dns_c_view_getprovideixfr(cview, &view->provideixfr);
    if (result != ISC_R_SUCCESS)
        result = dns_c_ctx_getprovideixfr(cctx, &view->provideixfr);
    if (result != ISC_R_SUCCESS)
        view->provideixfr = ISC_TRUE;

    /*
     * For now, there is only one kind of trusted keys, the
     * "security roots".
     */
    CHECK(configure_view_dnsseckeys(cview, cctx, mctx,
                  dns_c_view_gettrustedkeys,
                  dns_c_ctx_gettrustedkeys,
                  &view->secroots));

    {
        isc_uint32_t val;
        result = ISC_R_NOTFOUND;
        if (cview != NULL)
            result = dns_c_view_getmaxcachettl(cview, &val);
        if (result != ISC_R_SUCCESS)
            result = dns_c_ctx_getmaxcachettl(cctx, &val);
        if (result != ISC_R_SUCCESS)
            val = 7 * 24 * 3600;
        view->maxcachettl = val;
    }
    {
        isc_uint32_t val;
        result = ISC_R_NOTFOUND;
        if (cview != NULL)
            result = dns_c_view_getmaxncachettl(cview, &val);
        if (result != ISC_R_SUCCESS)
            result = dns_c_ctx_getmaxncachettl(cctx, &val);
        if (result != ISC_R_SUCCESS)
            val = 3 * 3600;
        if (val > 7 * 24 * 3600)
            val = 7 * 24 * 3600;
        view->maxncachettl = val;
    }

    result = ISC_R_SUCCESS;

 cleanup:
    RWUNLOCK(&view->conflock, isc_rwlocktype_write);

    for (sa = ISC_LIST_HEAD(addresses);
         sa != NULL;
         sa = next_sa) {
        next_sa = ISC_LIST_NEXT(sa, link);
        isc_mem_put(view->mctx, sa, sizeof *sa);
    }

    if (cmctx != NULL)
        isc_mem_detach(&cmctx);

    return (result);
}

/*
 * Create the special view that handles queries for
 * "version.bind. CH".   The version string returned is that
 * configured in 'cctx', or a compiled-in default if
 * there is no "version" configuration option.
 */
static isc_result_t
create_version_view(dns_c_ctx_t *cctx, dns_zonemgr_t *zmgr, dns_view_t **viewp)
{
    isc_result_t result;
    dns_db_t *db = NULL;
    dns_zone_t *zone = NULL;
    dns_dbversion_t *dbver = NULL;
    dns_difftuple_t *tuple = NULL;
    dns_diff_t diff;
    dns_view_t *view = NULL;
    char *versiontext;
    unsigned char buf[256];
    isc_region_t r;
    size_t len;
    dns_rdata_t rdata;
    static unsigned char origindata[] = "\007version\004bind";
    dns_name_t origin;

    REQUIRE(viewp != NULL && *viewp == NULL);

    CHECK(dns_view_create(ns_g_mctx, dns_rdataclass_ch, "_version",
                  &view));

    dns_diff_init(ns_g_mctx, &diff);

    dns_name_init(&origin, NULL);
    r.base = origindata;
    r.length = sizeof(origindata);
    dns_name_fromregion(&origin, &r);

    result = dns_c_ctx_getversion(cctx, &versiontext);
    if (result != ISC_R_SUCCESS)
        /*
         * Removing the const qualifier from ns_g_version is ok
         * because the resulting string is not modified, only
         * copied into a new buffer.
         */
        DE_CONST(ns_g_version, versiontext);

    len = strlen(versiontext);
    if (len > 255)
        len = 255; /* Silently truncate. */
    buf[0] = len;
    memcpy(buf + 1, versiontext, len);

    r.base = buf;
    r.length = 1 + len;
    dns_rdata_fromregion(&rdata, dns_rdataclass_ch, dns_rdatatype_txt, &r);

    CHECK(dns_zone_create(&zone, ns_g_mctx));
    CHECK(dns_zone_setorigin(zone, &origin));
    dns_zone_settype(zone, dns_zone_master);
    dns_zone_setclass(zone, dns_rdataclass_ch);
    dns_zone_setview(zone, view);

    CHECK(dns_zonemgr_managezone(zmgr, zone));

    CHECK(dns_db_create(ns_g_mctx, "rbt", &origin, dns_dbtype_zone,
                dns_rdataclass_ch, 0, NULL, &db));

    CHECK(dns_db_newversion(db, &dbver));

    CHECK(dns_difftuple_create(ns_g_mctx, DNS_DIFFOP_ADD, &origin,
                   0, &rdata, &tuple));
    dns_diff_append(&diff, &tuple);
    CHECK(dns_diff_apply(&diff, db, dbver));

    dns_db_closeversion(db, &dbver, ISC_TRUE);

    CHECK(dns_zone_replacedb(zone, db, ISC_FALSE));

    CHECK(dns_view_addzone(view, zone));

    dns_view_freeze(view);

    /* Transfer ownership. */
    *viewp = view;
    view = NULL;

    result = ISC_R_SUCCESS;

 cleanup:
    if (view != NULL)
        dns_view_detach(&view);
    if (zone != NULL)
        dns_zone_detach(&zone);
    if (dbver != NULL)
        dns_db_closeversion(db, &dbver, ISC_FALSE);
    if (db != NULL)
        dns_db_detach(&db);
    dns_diff_clear(&diff);

    return (result);
}

static isc_result_t
configure_hints(dns_view_t *view, const char *filename) {
    isc_result_t result;
    dns_db_t *db;

    db = NULL;
    result = dns_rootns_create(view->mctx, view->rdclass, filename, &db);
    if (result == ISC_R_SUCCESS) {
        dns_view_sethints(view, db);
        dns_db_detach(&db);
    }

    return (result);
}

/*
 * Find an existing view matching the name and class of 'cview'
 * in 'viewlist', or create a new one and add it to the list.
 *
 * If 'cview' is NULL, find or create the default view.
 *
 * The view found or created is attached to '*viewp'.
 */
static isc_result_t
find_or_create_view(dns_c_view_t *cview, dns_viewlist_t *viewlist,
            dns_view_t **viewp)
{
    isc_result_t result;
    const char *viewname;
    dns_rdataclass_t viewclass;
    dns_view_t *view = NULL;

    if (cview != NULL) {
        viewname = cview->name;
        result = dns_c_view_getviewclass(cview, &viewclass);
        if (result != ISC_R_SUCCESS)
            return (result);
    } else {
        viewname = "_default";
        viewclass = dns_rdataclass_in;
    }
    result = dns_viewlist_find(viewlist, viewname,
                   viewclass, &view);
    if (result == ISC_R_SUCCESS) {
        *viewp = view;
        return (ISC_R_SUCCESS);
    }
    if (result != ISC_R_NOTFOUND)
        return (result);
    INSIST(view == NULL);

    result = dns_view_create(ns_g_mctx, viewclass, viewname, &view);
    if (result != ISC_R_SUCCESS)
        return (result);

    ISC_LIST_APPEND(*viewlist, view, link);
    dns_view_attach(view, viewp);
    return (ISC_R_SUCCESS);
}

/*
 * Configure or reconfigure a zone.  This callback function
 * is called after parsing each "zone" statement in named.conf.
 */
static isc_result_t
configure_zone(dns_c_ctx_t *cctx, dns_c_zone_t *czone, dns_c_view_t *cview,
      void *uap)
{
    ns_load_t *lctx = (ns_load_t *) uap;
    dns_view_t *view = NULL;    /* New view */
    dns_view_t *pview = NULL;   /* Production view */
    dns_zone_t *zone = NULL;    /* New or reused zone */
    dns_zone_t *dupzone = NULL;

    isc_result_t result;

    char *corigin;
    isc_buffer_t buffer;
    dns_fixedname_t fixorigin;
    dns_name_t *origin;

    /*
     * Get the zone origin as a dns_name_t.
     */
    corigin = NULL;
    /* XXX casting away const */
    CHECK(dns_c_zone_getname(czone, (const char **) &corigin));
    isc_buffer_init(&buffer, corigin, strlen(corigin));
    isc_buffer_add(&buffer, strlen(corigin));
    dns_fixedname_init(&fixorigin);
    CHECK(dns_name_fromtext(dns_fixedname_name(&fixorigin),
                &buffer, dns_rootname, ISC_FALSE, NULL));
    origin = dns_fixedname_name(&fixorigin);

    /*
     * Find or create the view in the new view list.
     */
    view = NULL;
    CHECK(find_or_create_view(cview, &lctx->viewlist, &view));

    if (czone->zclass != view->rdclass) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
              "zone '%s': wrong class for view '%s'",
                  corigin, cview ? cview->name : "<default view>");
        result = ISC_R_FAILURE;
        goto cleanup;
    }

    /*
     * Master zones must have 'file' set.
     */
    if (czone->ztype == dns_c_zone_master &&
        czone->u.mzone.file == NULL) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "zone '%s': 'file' not specified",
                  corigin);
        result = ISC_R_FAILURE;
        goto cleanup;
    }

    /*
     * "hints zones" aren't zones.  If we've got one,
     * configure it and return.
     */
    if (czone->ztype == dns_c_zone_hint) {
        if (czone->u.hzone.file == NULL) {
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                      "zone '%s': 'file' not specified",
                      corigin);
            result = ISC_R_FAILURE;
            goto cleanup;
        }
        if (dns_name_equal(origin, dns_rootname)) {
            result = configure_hints(view, czone->u.hzone.file);
        } else {
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER, ISC_LOG_WARNING,
                      "ignoring non-root hint zone '%s'",
                      corigin);
            result = ISC_R_SUCCESS;
        }
        goto cleanup;
    }

    /*
     * "forward zones" aren't zones either.  Eventually we'll
     * translate this syntax into the appropriate selective forwarding
     * configuration.
     */
    if (czone->ztype == dns_c_zone_forward) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_WARNING,
      "forward zone '%s': forward zones are not supported in this release",
                  corigin);
        result = ISC_R_SUCCESS;
        goto cleanup;
    }

    /*
     * Check for duplicates in the new zone table.
     */
    result = dns_view_findzone(view, origin, &dupzone);
    if (result == ISC_R_SUCCESS) {
        /*
         * We already have this zone!
         */
        dns_zone_detach(&dupzone);
        result = ISC_R_EXISTS;
        goto cleanup;
    }
    INSIST(dupzone == NULL);

    /*
     * See if we can reuse an existing zone.  This is
     * only possible if all of these are true:
     *   - The zone's view exists
     *   - A zone with the right name exists in the view
     *   - The zone is compatible with the config
     *     options (e.g., an existing master zone cannot
     *     be reused if the options specify a slave zone)
     */
    result = dns_viewlist_find(&ns_g_server->viewlist,
                   view->name, view->rdclass,
                   &pview);
    if (result != ISC_R_NOTFOUND && result != ISC_R_SUCCESS)
        goto cleanup;
    if (pview != NULL)
        result = dns_view_findzone(pview, origin, &zone);
    if (result != ISC_R_NOTFOUND && result != ISC_R_SUCCESS)
        goto cleanup;
    if (zone != NULL) {
        if (! dns_zone_reusable(zone, czone))
            dns_zone_detach(&zone);
    }

    if (zone != NULL) {
        /*
         * We found a reusable zone.  Make it use the
         * new view.
         */
        dns_zone_setview(zone, view);
    } else {
        /*
         * We cannot reuse an existing zone, we have
         * to create a new one.
         */
        CHECK(dns_zone_create(&zone, lctx->mctx));
        CHECK(dns_zone_setorigin(zone, origin));
        dns_zone_setview(zone, view);
        CHECK(dns_zonemgr_managezone(ns_g_server->zonemgr, zone));
    }

    /*
     * Configure the zone.
     */
    CHECK(dns_zone_configure(cctx, cview, czone, lctx->aclconf, zone));

    /*
     * Add the zone to its view in the new view list.
     */
    CHECK(dns_view_addzone(view, zone));

 cleanup:
    if (zone != NULL)
        dns_zone_detach(&zone);
    if (pview != NULL)
        dns_view_detach(&pview);
    if (view != NULL)
        dns_view_detach(&view);

    return (result);
}

/*
 * Configure a single server quota.
 */
static void
configure_server_quota(dns_c_ctx_t *cctx,
               isc_result_t (*getquota)(dns_c_ctx_t *, isc_uint32_t *),
               isc_quota_t *quota, int defaultvalue)
{
    isc_uint32_t val = defaultvalue;
    (void)(*getquota)(cctx, &val);
    quota->max = val;
}

/*
 * This function is called as soon as the 'options' statement has been
 * parsed.
 */
static isc_result_t
options_callback(dns_c_ctx_t *cctx, void *uap) {
    isc_result_t result;

    UNUSED(uap);

    /*
     * Change directory.
     */
    if (cctx->options != NULL &&
        cctx->options->directory != NULL) {
        result = isc_dir_chdir(cctx->options->directory);
        if (result != ISC_R_SUCCESS) {
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER,
                      ISC_LOG_ERROR, "change directory "
                      "to '%s' failed: %s",
                      cctx->options->directory,
                      isc_result_totext(result));
            return (result);
        }
    }

    return (ISC_R_SUCCESS);
}


static void
scan_interfaces(ns_server_t *server, isc_boolean_t verbose) {
    ns_interfacemgr_scan(server->interfacemgr, verbose);
    dns_aclenv_copy(&server->aclenv,
            ns_interfacemgr_getaclenv(server->interfacemgr));
}

/*
 * This event callback is invoked to do periodic network
 * interface scanning.
 */
static void
interface_timer_tick(isc_task_t *task, isc_event_t *event) {
    ns_server_t *server = (ns_server_t *) event->ev_arg;
    UNUSED(task);
    isc_event_free(&event);
    RWLOCK(&server->conflock, isc_rwlocktype_write);
    scan_interfaces(server, ISC_FALSE);
    RWUNLOCK(&server->conflock, isc_rwlocktype_write);
}

static isc_result_t
load_configuration(const char *filename, ns_server_t *server,
           isc_boolean_t first_time)
{
    isc_result_t result;
    ns_load_t lctx;
    dns_c_cbks_t callbacks;
    dns_c_ctx_t *cctx;
    dns_view_t *view = NULL;
    dns_view_t *view_next;
    dns_viewlist_t tmpviewlist;
    dns_aclconfctx_t aclconfctx;
    dns_dispatch_t *dispatchv4 = NULL;
    dns_dispatch_t *dispatchv6 = NULL;
    char *pidfilename;
    isc_uint32_t interface_interval;
    in_port_t listen_port;

    dns_aclconfctx_init(&aclconfctx);

    RWLOCK(&server->conflock, isc_rwlocktype_write);
    dns_zonemgr_lockconf(server->zonemgr, isc_rwlocktype_write);

    lctx.mctx = ns_g_mctx;
    lctx.aclconf = &aclconfctx;
    ISC_LIST_INIT(lctx.viewlist);

    callbacks.zonecbk = configure_zone;
    callbacks.zonecbkuap = &lctx;
    callbacks.optscbk = options_callback;
    callbacks.optscbkuap = NULL;

    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_INFO, "loading configuration from '%s'",
              filename);

    /*
     * Parse the configuration file creating a parse tree.  Any
     * 'zone' statements are handled immediately by calling
     * configure_zone() through 'callbacks'.
     */
    cctx = NULL;
    CHECK(dns_c_parse_namedconf(filename, ns_g_mctx, &cctx,
                    &callbacks));

    /*
     * Configure various server options.
     */
    configure_server_quota(cctx, dns_c_ctx_gettransfersout,
                     &server->xfroutquota, 10);
    configure_server_quota(cctx, dns_c_ctx_gettcpclients,
                     &server->tcpquota, 100);
    configure_server_quota(cctx, dns_c_ctx_getrecursiveclients,
                     &server->recursionquota, 100);

    /*
     * Configure the zone manager.
     */
    {
        isc_uint32_t transfersin = 10;
        (void)dns_c_ctx_gettransfersin(cctx, &transfersin);
        dns_zonemgr_settransfersin(server->zonemgr, transfersin);
    }
    {
        isc_uint32_t transfersperns = 2;
        (void)dns_c_ctx_gettransfersperns(cctx, &transfersperns);
        dns_zonemgr_settransfersperns(server->zonemgr, transfersperns);
    }

    /*
     * Determine which port to use for listening for incoming connections.
     */
    if (ns_g_port != 0) {
        listen_port = ns_g_port;
    } else {
        result = dns_c_ctx_getport(cctx, &listen_port);
        if (result != ISC_R_SUCCESS)
            listen_port = 53;
    }
    /*
     * Configure the interface manager according to the "listen-on"
     * statement.
     */
    {
        dns_c_lstnlist_t *clistenon = NULL;
        ns_listenlist_t *listenon = NULL;

        (void)dns_c_ctx_getlistenlist(cctx, &clistenon);
        if (clistenon != NULL) {
            result = ns_listenlist_fromconfig(clistenon,
                              cctx,
                              &aclconfctx,
                              ns_g_mctx,
                              &listenon);
        } else {
            /*
             * Not specified, use default.
             */
            CHECK(ns_listenlist_default(ns_g_mctx, listen_port,
                            ISC_TRUE, &listenon));
        }
        ns_interfacemgr_setlistenon4(server->interfacemgr, listenon);
        ns_listenlist_detach(&listenon);
    }
    /*
     * Ditto for IPv6.
     */
    {
        dns_c_lstnlist_t *clistenon = NULL;
        ns_listenlist_t *listenon = NULL;

        (void)dns_c_ctx_getv6listenlist(cctx, &clistenon);
        if (clistenon != NULL) {
            result = ns_listenlist_fromconfig(clistenon,
                              cctx,
                              &aclconfctx,
                              ns_g_mctx,
                              &listenon);
        } else {
            /*
             * Not specified, use default.
             */
            CHECK(ns_listenlist_default(ns_g_mctx, listen_port,
                            ISC_FALSE, &listenon));
        }
        ns_interfacemgr_setlistenon6(server->interfacemgr, listenon);
        ns_listenlist_detach(&listenon);
    }

    /*
     * Rescan the interface list to pick up changes in the
     * listen-on option.  It's important that we do this before we try
     * to configure the query source, since the dispatcher we use might
     * be shared with an interface.
     */
    scan_interfaces(server, ISC_TRUE);

    /*
     * Arrange for further interface scanning to occur periodically
     * as specified by the "interface-interval" option.
     */
    interface_interval = 3600; /* Default is 1 hour. */
    (void)dns_c_ctx_getinterfaceinterval(cctx, &interface_interval);
    if (interface_interval == 0) {
        isc_timer_reset(server->interface_timer,
                isc_timertype_inactive,
                NULL, NULL, ISC_TRUE);
    } else {
        isc_interval_t interval;
        isc_interval_set(&interval, interface_interval, 0);
        isc_timer_reset(server->interface_timer, isc_timertype_ticker,
                NULL, &interval, ISC_FALSE);
    }

    /*
     * Configure and freeze all explicit views.  Explicit
     * views that have zones were already created at parsing
     * time, but views with no zones must be created here.
     */
    if (cctx->views != NULL) {
        dns_c_view_t *cview;
        for (cview = ISC_LIST_HEAD(cctx->views->views);
             cview != NULL;
             cview = ISC_LIST_NEXT(cview, next))
        {
            view = NULL;
            CHECK(find_or_create_view(cview,
                          &lctx.viewlist, &view));
            INSIST(view != NULL);
            CHECK(configure_view(view, cctx, cview, ns_g_mctx,
                         &aclconfctx));
            dns_view_freeze(view);
            dns_view_detach(&view);
        }
    }
    INSIST(view == NULL);

    /*
     * Make sure we have a default view if and only if there
     * were no explicit views.
     */
    if (cctx->views == NULL || ISC_LIST_EMPTY(cctx->views->views)) {
        /*
         * No explicit views; there ought to be a default view.
         * There may already be one created as a size effect
         * of zone statements, or we may have to create one.
         * In either case, we need to configure and freeze it.
         */
        CHECK(find_or_create_view(NULL, &lctx.viewlist, &view));
        CHECK(configure_view(view, cctx, NULL,
                     ns_g_mctx, &aclconfctx));
        dns_view_freeze(view);
        dns_view_detach(&view);
    } else {
        /*
         * There are explicit views.  There should not be
         * a default view.  If there is one, complain.
         */
        result = dns_viewlist_find(&lctx.viewlist, "_default",
                       dns_rdataclass_in, &view);
        if (result == ISC_R_SUCCESS) {
            dns_view_detach(&view);
            isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                      NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                      "when using 'view' statements, "
                      "all zones must be in views");
            result = ISC_R_FAILURE;
            goto cleanup;
        }
    }

    /*
     * Create (or recreate) the version view.
     */
    view = NULL;
    CHECK(create_version_view(cctx, server->zonemgr, &view));
    ISC_LIST_APPEND(lctx.viewlist, view, link);
    view = NULL;

    /*
     * Swap our new view list with the production one.
     */
    tmpviewlist = server->viewlist;
    server->viewlist = lctx.viewlist;
    lctx.viewlist = tmpviewlist;

    /*
     * Load the TKEY information from the configuration.
     */
    {
        dns_tkeyctx_t *t = NULL;
        CHECKM(dns_tkeyctx_fromconfig(cctx, ns_g_mctx, ns_g_entropy,
                          &t),
               "configuring TKEY");
        if (server->tkeyctx != NULL)
            dns_tkeyctx_destroy(&server->tkeyctx);
        server->tkeyctx = t;
    }

    /*
     * Bind the OMAPI port(s).
     */
    CHECKM(ns_omapi_configure(ns_g_mctx, cctx, &aclconfctx),
           "binding control channel(s)");

    /*
     * Relinquish root privileges.
     */
    if (first_time)
        ns_os_changeuser();

    /*
     * Configure the logging system.
     *
     * Do this after changing UID to make sure that any log
     * files specified in named.conf get created by the
     * unprivileged user, not root.
     */
    if (ns_g_logstderr) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_INFO,
                  "ignoring config file logging "
                  "statement due to -g option");
    } else {
        dns_c_logginglist_t *clog = NULL;
        isc_logconfig_t *logc = NULL;

        CHECKM(isc_logconfig_create(ns_g_lctx, &logc),
               "creating new logging configuration");

        (void)dns_c_ctx_getlogging(cctx, &clog);
        if (clog != NULL) {
            CHECKM(ns_log_configure(logc, clog),
                   "configuring logging");
        } else {
            CHECKM(ns_log_setdefaultchannels(logc),
                   "setting up default logging channels");
            CHECKM(ns_log_setdefaultcategory(logc),
                   "setting up default 'category default'");
        }

        result = isc_logconfig_use(ns_g_lctx, logc);
        if (result != ISC_R_SUCCESS) {
            isc_logconfig_destroy(&logc);
            CHECKM(result, "installing logging configuration");
        }

        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_DEBUG(1),
                  "now using logging configuration from "
                  "config file");
    }

    if (dns_c_ctx_getpidfilename(cctx, &pidfilename) != ISC_R_NOTFOUND)
        ns_os_writepidfile(pidfilename);
    else
        ns_os_writepidfile(ns_g_defaultpidfile);

    dns_aclconfctx_destroy(&aclconfctx);

    dns_c_ctx_delete(&cctx);

 cleanup:
    /*
     * This cleans up either the old production view list
     * or our temporary list depending on whether they
     * were swapped above or not.
     */
    for (view = ISC_LIST_HEAD(lctx.viewlist);
         view != NULL;
         view = view_next) {
        view_next = ISC_LIST_NEXT(view, link);
        ISC_LIST_UNLINK(lctx.viewlist, view, link);
        dns_view_detach(&view);

    }

    if (dispatchv4 != NULL)
        dns_dispatch_detach(&dispatchv4);
    if (dispatchv6 != NULL)
        dns_dispatch_detach(&dispatchv6);

    dns_zonemgr_unlockconf(server->zonemgr, isc_rwlocktype_write);
    RWUNLOCK(&server->conflock, isc_rwlocktype_write);
    return (result);
}

static isc_result_t
load_zones(ns_server_t *server, isc_boolean_t stop) {
    isc_result_t result;
    dns_view_t *view;

    dns_zonemgr_lockconf(server->zonemgr, isc_rwlocktype_read);

    /*
     * Load zone data from disk.
     */
    for (view = ISC_LIST_HEAD(server->viewlist);
         view != NULL;
         view = ISC_LIST_NEXT(view, link))
    {
        CHECK(dns_view_load(view, stop));
    }

    /*
     * Force zone maintenance.  Do this after loading
     * so that we know when we need to force AXFR of
     * slave zones whose master files are missing.
     */
    CHECK(dns_zonemgr_forcemaint(server->zonemgr));
 cleanup:
    dns_zonemgr_unlockconf(server->zonemgr, isc_rwlocktype_read);
    return (result);
}

static void
run_server(isc_task_t *task, isc_event_t *event) {
    isc_result_t result;
    ns_server_t *server = (ns_server_t *)event->ev_arg;

    UNUSED(task);

    isc_event_free(&event);

    CHECKFATAL(dns_dispatchmgr_create(ns_g_mctx, ns_g_entropy,
                      &ns_g_dispatchmgr),
           "creating dispatch manager");

    CHECKFATAL(ns_clientmgr_create(ns_g_mctx, ns_g_taskmgr, ns_g_timermgr,
                       &server->clientmgr),
           "creating client manager");

    CHECKFATAL(ns_interfacemgr_create(ns_g_mctx, ns_g_taskmgr,
                      ns_g_socketmgr, ns_g_dispatchmgr,
                      server->clientmgr,
                      &server->interfacemgr),
           "creating interface manager");

    CHECKFATAL(isc_timer_create(ns_g_timermgr, isc_timertype_inactive,
                    NULL, NULL, server->task,
                    interface_timer_tick,
                    server, &server->interface_timer),
           "creating interface timer");

    CHECKFATAL(load_configuration(ns_g_conffile, server, ISC_TRUE),
           "loading configuration");

    CHECKFATAL(load_zones(server, ISC_TRUE),
           "loading zones");

    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_INFO, "running");
}

static void
shutdown_server(isc_task_t *task, isc_event_t *event) {
    dns_view_t *view, *view_next;
    ns_server_t *server = (ns_server_t *)event->ev_arg;

    UNUSED(task);

    RWLOCK(&server->conflock, isc_rwlocktype_write);

    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_INFO, "shutting down");

    for (view = ISC_LIST_HEAD(server->viewlist);
         view != NULL;
         view = view_next) {
        view_next = ISC_LIST_NEXT(view, link);
        ISC_LIST_UNLINK(server->viewlist, view, link);
        dns_view_detach(&view);
    }

    ns_clientmgr_destroy(&server->clientmgr);
    isc_timer_detach(&server->interface_timer);

    ns_interfacemgr_shutdown(server->interfacemgr);
    ns_interfacemgr_detach(&server->interfacemgr);

    dns_dispatchmgr_destroy(&ns_g_dispatchmgr);

    dns_zonemgr_shutdown(server->zonemgr);

    isc_task_detach(&server->task);

    isc_event_free(&event);

    RWUNLOCK(&server->conflock, isc_rwlocktype_write);
}

void
ns_server_create(isc_mem_t *mctx, ns_server_t **serverp) {
    isc_result_t result;

    ns_server_t *server = isc_mem_get(mctx, sizeof(*server));
    if (server == NULL)
        fatal("allocating server object", ISC_R_NOMEMORY);

    server->mctx = mctx;
    server->task = NULL;

    CHECKFATAL(isc_rwlock_init(&server->conflock, 1, 1),
           "initializing server configuration lock");

    /* Initialize configuration data with default values. */

    result = isc_quota_init(&server->xfroutquota, 10);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);
    result = isc_quota_init(&server->tcpquota, 10);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);
    result = isc_quota_init(&server->recursionquota, 100);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);

    result = dns_aclenv_init(mctx, &server->aclenv);
    RUNTIME_CHECK(result == ISC_R_SUCCESS);

    /* Initialize server data structures. */
    server->zonemgr = NULL;
    server->clientmgr = NULL;
    server->interfacemgr = NULL;
    ISC_LIST_INIT(server->viewlist);
    server->in_roothints = NULL;

    CHECKFATAL(dns_rootns_create(mctx, dns_rdataclass_in, NULL,
                     &server->in_roothints),
           "setting up root hints");

    CHECKFATAL(isc_mutex_init(&server->reload_event_lock),
           "initializing reload event lock");
    server->reload_event =
        isc_event_allocate(ns_g_mctx, server,
                   NS_EVENT_RELOAD,
                   ns_server_reload,
                   server,
                   sizeof(isc_event_t));
    CHECKFATAL(server->reload_event == NULL ?
           ISC_R_NOMEMORY : ISC_R_SUCCESS,
           "allocating reload event");

    CHECKFATAL(dst_lib_init(ns_g_mctx, ns_g_entropy, 0),
           "initializing DST");

    server->tkeyctx = NULL;
    CHECKFATAL(dns_tkeyctx_create(ns_g_mctx, ns_g_entropy,
                      &server->tkeyctx),
           "creating TKEY context");

    /*
     * Setup the server task, which is responsible for coordinating
     * startup and shutdown of the server.
     */
    CHECKFATAL(isc_task_create(ns_g_taskmgr, 0, &server->task),
           "creating server task");
    isc_task_setname(server->task, "server", server);
    CHECKFATAL(isc_task_onshutdown(server->task, shutdown_server, server),
           "isc_task_onshutdown");
    CHECKFATAL(isc_app_onrun(ns_g_mctx, server->task, run_server, server),
           "isc_app_onrun");

    server->interface_timer = NULL;
    /*
     * Create a timer for periodic interface scanning.
     */
    CHECKFATAL(dns_zonemgr_create(ns_g_mctx, ns_g_taskmgr, ns_g_timermgr,
                      ns_g_socketmgr, &server->zonemgr),
           "dns_zonemgr_create");

    server->magic = NS_SERVER_MAGIC;
    *serverp = server;
}

void
ns_server_destroy(ns_server_t **serverp) {
    ns_server_t *server = *serverp;
    REQUIRE(NS_SERVER_VALID(server));

    dns_zonemgr_detach(&server->zonemgr);

    if (server->tkeyctx != NULL)
        dns_tkeyctx_destroy(&server->tkeyctx);

    dst_lib_destroy();

    isc_event_free(&server->reload_event);

    INSIST(ISC_LIST_EMPTY(server->viewlist));

    dns_db_detach(&server->in_roothints);

    dns_aclenv_destroy(&server->aclenv);

    isc_quota_destroy(&server->recursionquota);
    isc_quota_destroy(&server->tcpquota);
    isc_quota_destroy(&server->xfroutquota);
    isc_rwlock_destroy(&server->conflock);

    server->magic = 0;
    isc_mem_put(server->mctx, server, sizeof(*server));
}

static void
fatal(const char *msg, isc_result_t result) {
    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_CRITICAL, "%s: %s", msg,
              isc_result_totext(result));
    isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_SERVER,
              ISC_LOG_CRITICAL, "exiting (due to fatal error)");
    exit(1);
}

static void
ns_server_reload(isc_task_t *task, isc_event_t *event) {
    isc_result_t result;
    ns_server_t *server = (ns_server_t *)event->ev_arg;
    UNUSED(task);

    result = load_configuration(ns_g_conffile, server, ISC_FALSE);
    if (result != ISC_R_SUCCESS) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "reloading configuration failed: %s",
                  isc_result_totext(result));
    }
    result = load_zones(server, ISC_FALSE);
    if (result != ISC_R_SUCCESS) {
        isc_log_write(ns_g_lctx, NS_LOGCATEGORY_GENERAL,
                  NS_LOGMODULE_SERVER, ISC_LOG_ERROR,
                  "reloading zones failed: %s",
                  isc_result_totext(result));
    }
    LOCK(&server->reload_event_lock);
    INSIST(server->reload_event == NULL);
    server->reload_event = event;
    UNLOCK(&server->reload_event_lock);
}

void
ns_server_reloadwanted(ns_server_t *server) {
    LOCK(&server->reload_event_lock);
    if (server->reload_event != NULL)
        isc_task_send(server->task, &server->reload_event);
    UNLOCK(&server->reload_event_lock);
}

static isc_result_t
ns_listenlist_fromconfig(dns_c_lstnlist_t *clist, dns_c_ctx_t *cctx,
              dns_aclconfctx_t *actx,
              isc_mem_t *mctx, ns_listenlist_t **target)
{
    dns_c_lstnon_t *ce;
    isc_result_t result;
    ns_listenlist_t *dlist = NULL;

    REQUIRE(target != NULL && *target == NULL);

    result = ns_listenlist_create(mctx, &dlist);
    if (result != ISC_R_SUCCESS)
        return (result);

    for (ce = ISC_LIST_HEAD(clist->elements);
         ce != NULL;
         ce = ISC_LIST_NEXT(ce, next))
    {
        ns_listenelt_t *delt = NULL;
        result = ns_listenelt_fromconfig(ce, cctx, actx, mctx, &delt);
        if (result != ISC_R_SUCCESS)
            goto cleanup;
        ISC_LIST_APPEND(dlist->elts, delt, link);
    }
    *target = dlist;
    return (ISC_R_SUCCESS);

 cleanup:
    ns_listenlist_detach(&dlist);
    return (result);
}

/*
 * Create a listen list from the corresponding configuration
 * data structure.
 */
static isc_result_t
ns_listenelt_fromconfig(dns_c_lstnon_t *celt, dns_c_ctx_t *cctx,
             dns_aclconfctx_t *actx,
             isc_mem_t *mctx, ns_listenelt_t **target)
{
    isc_result_t result;
    ns_listenelt_t *delt = NULL;
    REQUIRE(target != NULL && *target == NULL);
    result = ns_listenelt_create(mctx, celt->port, NULL, &delt);
    if (result != ISC_R_SUCCESS)
        return (result);

    result = dns_acl_fromconfig(celt->iml, cctx, actx, mctx, &delt->acl);
    if (result != ISC_R_SUCCESS) {
        ns_listenelt_destroy(delt);
        return (result);
    }
    *target = delt;
    return (ISC_R_SUCCESS);
}